Updated 13 April 2017

Cutting your cancer risk

We can make a difference to our chances of contracting cancer. Judy Bass and Joanne Lillie suggest the following lifestyle changes.

Will you get cancer? Most of us think our fate is sealed, thanks to our genetic make-up. But a study published in the New England Journal of Medicine looked at the health histories of 45000 twins and found that what they ate and how much they exercised had much more influence on their cancer risk than heredity alone.

“There’s good scientific evidence that more than half of cancer cases could be prevented if people made certain lifestyle changes,” comments David Hunter, director of the Harvard Centre for Cancer Prevention in Boston, USA.

The message is that you have more control of your cancer risk than you think. Of course, there’s no guarantee that you won’t get cancer; it’s caused by a combination of factors that continue to puzzle scientists.

But researchers have confirmed the protective power of certain habits, like maintaining a healthy weight and wearing sunscreen.

Considering that one in two men and one in three women will develop some form of the disease in their lifetime, it’s wise to act now. Here are the questions to ask yourself:

Do you limit your alcohol intake?Here’s why you should: You’ve probably heard a lot about the heart benefits of red wine, but it’s important to restrict how much you drink because alcohol increases your cancer risk. Researchers are exploring several possible links between alcohol and cancer.

Alcohol increases the oestrogen circulating in your body, which can increase your risk of hormone-related cancers.

Drinking reduces your body’s levels of folic acid (a B vitamin), and a deficiency in this nutrient appears to be a risk factor for cancers of the cervix, colon, rectum, lungs, oesophagus and brain.

Alcohol metabolises to acetaldehyde, a substance that may cause cancer in laboratory animals.

Risk reducers:

Be moderate. Restrict yourself to one glass of wine, a beer, or two shots (30ml) of spirits a day.

Supplement with B vitamins. Because folic acid deficiency may increase your risk of cancer, consider taking a daily B-complex vitamin if you drink.

Science says:

A Swedish study followed 9353 diagnosed alcoholics for an average of eight years and found they were 4.1 times more likely than non-drinkers to develop cancer of the mouth and pharynx, and 6.8 times more likely to develop cancer of the oesophagus.

Have you cut down on red meat?Here’s why you should: Researchers agree that regular and excess red meat consumption increases your risk of cancers of the colon, rectum, stomach, breast and prostate. One theory is that cooking animal proteins at high temperatures, including braaing, produces carcinogens.

Risk reducers:

Cut back. Limit your consumption to one or two times a week. Your portion sizes should be small — no more than 85g after cooking — about the size of a pack of cards. Also, buy organically and ethically farmed meat where possible. It should be free of potential carcinogens such as bovine growth hormone.

Replace the red. Opt instead for grain-based protein sources, such as beans, soya, nuts and seeds.

Science says:

A study published in the International Journal of Cancer noted that people who ate red meat seven or more times per week were 90% more likely to develop colon cancer, 70% more likely to develop rectal cancer, and 60% more likely to develop stomach cancer than those who ate it three times a week.

Do you drink green tea?Here’s why you should: “When people ask me, ‘What is the single best cancer fighter?’ I usually put green tea up there at the top,” says Mitchell Gaynor, an oncology academic. The major antioxidant in green tea, EGCG, has 20 times more free-radical fighting power than vitamin E and 200 times more than vitamin C. It also inhibits chemicals that tumours need to grow and divide, including COX-2 enzyme, which makes carcinogens more active in the body, he says.

Risk reducers:

Brew a cup. To make green tea, pour two cups of almost boiling water over one teaspoon of green tea leaves. Steep for three to five minutes. To get the most antioxidant benefit, don’t add milk and drink immediately. Aim to drink three cups a day, which has shown the best results in studies.

Science says:

According to a Chinese study published in the Journal of the National Cancer Institute, women who drank two to three cups of green tea a day cut their risk of oesophageal cancer by 60%. Men who drank the same amount reduced their risk by 57%.

Do you avoid home pesticides?Here’s why you should: Avoiding home and garden pesticides “is probably one of the most important things you can do around the home to cut the risk of cancer,” says David Steinman, co-author of The Breast Cancer Prevention Program (IDG). A German study published in the Journal of Epidemiology found a link between household pesticides and childhood cancers.

Risk reducers:

Go non-toxic in the garden. If your outdoor plants are infested with aphids, beetles or caterpillars, rather use insecticidal soap, available at most garden centres.

Clear clutter. To discourage ants and cockroaches, clear all old newspapers, clothes and bottles from countertops, cupboards and draws. Keep these areas clean and dry. To deter ants, place balls of cotton wool soaked in peppermint essential oil or a sprinkle of cayenne pepper on windowsills or doorframes. If you do need professional exterminators, ask them to use boric acid on infested areas; it’s less toxic than other kinds of pesticides.

Science says:

The US Environmental Protection Agency stated back in 1995 that sticky pest strips (such as the ones used to trap flies) created an increased cancer risk. People who use them as directed over the course of a lifetime have as much as a one in 100 chance of developing a cancer.

Have you stopped smoking?Here’s why you should: Smoking, the largest preventable cause of cancer, accounts for 30% of all cancers estimates Dr Carl Albrecht, chief researcher at the Cancer Association of South Africa (CANSA). Smoking is linked not only to lung cancer, but also to cancer of the mouth, larynx, oesophagus, bladder, kidney, pancreas and cervix.

Risk reducers:

Make new habits. Yes, it’s easier said than done, but when you feel the urge to smoke, try meditative breathing. Take 10 deep breaths in and out of your nose, causing your stomach to expand and contract. This mimics the sensation of taking a drag on a cigarette and gives you the mental break that smoking provides.

Turn to a professional. Acupuncture and hypnosis help some people conquer nicotine cravings. Others have turned to the advice of the National Council Against Smoking helpline on 011-7203145.

Science says:

Research has shown that 25000 people die from smoking-related diseases in South Africa every year.

Have you shed that extra weight?Here’s why you should: Being overweight appears to put you at greater risk for certain cancers, especially colon and breast cancers, because overweight people tend to produce too much of the hormone insulin. Researchers theorise that when your pancreas secretes insulin, your liver secretes substances called insulin-like growth factors (IGFs), which some cancer experts regard as potent tumour and cancer cell promoters.

“If fewer South Africans were overweight, we could reduce the rate of cancer in the country,” says Joel Perry, Head of Health Programmes at CANSA. Further, a recent report by the World Health Organisation’s International Agency for Research on Cancer estimates that being overweight and inactive accounts for one-fifth to one-third of all breast, colon, endometrial, kidney and oesophageal cancers.

Risk reducers:

Work out your Body Mass Index (BMI). Divide your weight by your height squared. The range of healthy weight is 18.5 to 24.9, according to the international Centres for Disease Control.

Take an active approach. To keep your weight within a healthy range, eat a sensible diet and exercise most days of the week. Make it a priority, you don’t need to do anything fancy or expensive — just get moving on a regular basis.

Science says:

Statistics from the Harvard Centre for Cancer Prevention show that women who are 40% above their ideal weight have a 55% greater chance of developing cancers of the breast, ovaries and gall bladder than leaner women. Men who are 40% over their ideal weight have a 33% higher chance of developing colon and prostate cancers. Alarmingly, 55% of all South African women across all ethnicity groups are overweight, says the Heart and Stroke Foundation of SA.

Do you eat enough fibre?Here’s why you should: Researchers believe fibre cuts your risk of cancer by binding to carcinogens in your intestines and sweeping them out of your body.One in 131 South African women is at risk of getting colorectal cancer. Fibre-rich foods provide benefits beyond roughage. They’re also loaded with phytonutrients that have a variety of effects, such as quenching free radicals. Perry emphasises that healthy lifestyle choices can reduce your risk of these cancers significantly.

Keep track. Aim to consume 20 to 35g of fibre a day. One cup of broccoli has 5g, one large unpeeled apple has almost 6g, and half a cup of tinned baked beans also contains 6g.

Science says:

In an article published in the Journal of the National Cancer Institute, researchers analysed 13 studies and found that people who ate the most fibre were between 21 and 47% less likely to develop colorectal cancer than those who ate the least.

Do you avoid the sun?

Here’s why you should: Skin cancer, one of the most common forms of cancer, is usually caused by damage to skin cells by the sun’s ultraviolet (UV) light. Do what you can all-year-round to avoid the sun for long periods. Your dermatologist will tell you: there is no such thing as a healthy tan.

Risk reducers:

Start a sunscreen habit. Apply a sunscreen of SPF 15 or more on your face and the back of your hands every morning, even on overcast days. Reapply frequently if you’re swimming or exercising. “The biggest mistake people make with sunscreen is not applying enough of the product. Manufacturers have an internationally agreed application thickness of 2mg per square centimetre,” says CANSA.

Cover up. Limit your time outdoors when the amount of solar UV radiation is greatest — 10am to 3pm in SA. If you must be outside, stay in the shade, wear long sleeves and a hat with a brim, along with the essential UV-blocking sunglasses.

Science says:Researchers expect an increase in skin cancer cases as the ozone layer continues to thin. Reports from the last 30 years suggest that rates of malignant melanoma, the deadliest form, have increased by over 120%. And children must be protected: just one bad sunburn before age 16 increases melanoma risk three to five times.

Ask the Expert

CANSA’s purpose is to lead the fight against cancer in South Africa. Its mission is to be the preferred non-profit organisation that enables research, educates the public and provides support to all people affected by cancer. Questions are answered by CANSA’s Head of Health Professor Michael Herbst. For more information, visit cansa.org.za.

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